I think the definitions of Virtual Assistant in this image start to explain what a (human) Virtual Assistant is. Essentially a Virtual Assistant will work on a defined task, project or area of your business, giving you the time to focus on what you need to. The word 'professional' appears in each definition above and this is really important. A Virtual Assistant will most likely be running their own business and will have a wealth of knowledge, experience and contacts. Their livelihood is dependant on providing a great service, so you will find a Virtual Assistant will get to know your business and will become a big champion for the product or service you offer.
So, if you want to know what the weather will be like tomorrow, get an Alexa (disclaimer: other smart speakers are available). If you want a professional who will efficiently handle a range of tasks adding value and time to your business, get a Virtual Assistant.